Wood treatment



United States Patent WOOD TREATMENT No Drawing. Application December 22, 1955 Serial No. 554,641

8 Claims. (Cl. 167--38.7)

The instant invention relates to the treatment of wood, and more particularly, to anti-blooming agents for use in wood preservation and improved methods of preserving wood by the use of such anti-blooming agents.

Although various compounds are known for the pres ervation of wood, pentachlorophenol has met with great commercial acceptance. In the usual wood preserving process, pentachlorophenol dissolved in a suitable solvent is brought into contact with the wood, as by dipping the wood in the solution, and the wood is then removed and dried. The pentachlorophenol, of course, penetrates into the wood and to a substantial extent remains impregnated in the wood after the solvent has been dried or removed. One difiiculty, however, is that there is a tendency for some of the pentachlorophenol to leach back out of the wood during the drying process and, after the wood is dried, there appears a light colored crystalline coating on the surface of the wood which may be easily rubbed off (and is thus ineffective for wood preservation purposes). This results in an undesirable appearance as wellas an undesirable loss of material. non is referred to as blooming in the industry.

The exact causes of blooming are not fully understood in the industry, but the problem has persisted for a number of years. Various anti-blooming agents may have been suggested from time to time but each has left something to be desired.

The instant invention resides in the discovery that certain compounds, which will be referred to generally hereinafter as amido compounds (but which are described in detail in the specification) may be used in conjunction with pentachlorophenol, in solution, during treatment or impregnation of the wood so as to materially reduce or substantially eliminate blooming. These amido compounds which have been found to have unique anti-blooming properties include only a very specific class of compounds. The peculiar manner in which these antiblooming agents apparently cooperate with pentachlorophenol cannot be fullyunderstood, but the unusual results speak for themselves, as will be shown hereinafter.

It is, therefore, an important object of the instant invention to provide .a unique anti-blooming agent for the treatment of wood; and to provide an improved Wood preservation process. 7

It is .a furtherobject of the instant invention to provide a wood treating composition comprising pentachlorophenol and an N-dialkylaminoalkyleneamide or salt thereof, and it is yet another object of the instant invention to provide an-improved method of treating wood which comprises contacting the wood with said composition. 7 Otherand .further, objects, features and advantages of the present invention .will become apparent to those skilled in lthe a'r t from itlie'following "detailed disclosure thereof. ,The instant .inventionconsists in ,a composition comprising pentachlorophenol and an amido compound, dis- This phenomegqiveeupajcdmmon 'solveh't,j,th1e, concentration oflthe pentachlorophenol being 1% to 30% and the concentraice tion of the amido compound being /2 to 10 times the pentachlorophenol concentration, said amido compound being selected from compounds having the formulae wherein RC0 is an acyl group derived from a carboxylic acid selected from Gig-C20 fatty acids and rosin acids, A is a C -C alkylene group, R is a radical selected from the group consisting of H and C -C alkyl radicals, and R" is a C -C alkyl radical; and a method of treating wood which comprises contacting the wood with said composition and then drying the wood.

Although mono and polychlorophenols are generally known to have Wood preserving properties, and particularly chloro-2-phenylphenol, tetrachlorophenol as well as pentachlorophenol (any of such mono and/ or polychlorophenols may be used in the practice of the instant invention), pentachlorophenol, tetrachlorophenol and chloro- 2-phenylphenol are the members of this group which have met with the most general commercial acceptance. Actually, commercial pentachlorophenol (which is used in the following examples) is predominantly pentachlorophenol although it contains an appreciable amount of tetrachlorophenol also. The commercial analysis is 83% pentachlorophenol, 12% tetrachlorophenol and 5% inerts.

The instant invention does not involve a departure from the use of previously employed pentachlorophenol solutions or the previously employed process steps for the use of such solutions, with the exception that the instant anti-blooming agent isincluded in the solution and is use in conjunction with the pentachlorophenol. Pentachlorophenol solutions for this commercial purpose are well known in the art. The solutions may have concentrations within the range of 1% to 30% pentachlorophenol. (As used herein, the terms parts and percent mean parts and percent by weight unless otherwise indicated.) Preferably, the pentachlorophenol concentration is within the range of about 3% to about 8%, and the best results are ordinarily obtained using 5% pentachlorophenol in the solution.

The solvents used in commercial practice are all relatively slowly volatile solvents and, of course, since such solvents are lost during the drying process to a substantial extent, economic considerations are involved. In general, hydrocarbon solvents are employed. Preferred solvents include mineral spirits, xylene, etc. boiling Within the range of C. to about 200 C. In this way bath temperatures of substantially greater than room temperature may be used so as to obtain better solution of the pentachlorophenol and the amido compound and more efiective and more rapid penetration of the wood, al though bath temperatures for the solution (in which the wood is usually dipped) may range from 0 C. to as much as about 40 C. (in open treating vessels).

The concentration of the amido compound used in the practice of the instant invention depends to a certain extent upon the concentration of the pentachlorophenol and, in general, the concentration of the amido compound may range from a minimum of about /2 to a maximum of about 10 times the pentachlorophenol concentration. Expressed in other terms, the amido compound concentration may range from a minimum effective amount of about /2% to a maximum effective amount of perhaps 30%, the total of the pentachlorophenol and amido compound concentrations should not, ordinarily, exceed about 50% in order to maintain effective solution of both ingredients in the solvent, at usual working temperatures. In the preferred ranges of pentachlorophenol concentration it is generally preferable to employ an amido compound concentration that is substantially equal to the pentachlorophenol concentration, and it has been found that the best results are obtained using substantially a pentachlorophenol concentration and substantially an equal amido compound concentration.

As indicated previously, the amido compound used in the practice of the invention is an N-dialkylaminoalkyleneamide or salt thereof. In each case, the amide is an amide of a high molecular weight acid and the salt is a salt of a high molecular weight organic acid. Certain derivatives of 3-dimethylaminopropylamine and fatty acids and/ or rosin acids are preferred.

Suitable N-dialkylaminoalkylamide compounds of the indicated type are illustrated in the following formula:

Where RCO- represents an acyl group derived from a carboxylic acid, i. e., from a fatty acid containing 12 to carbon atoms or from a rosin acid; A represents an alkyl ene group containing 2 to 6 carbon atoms; R represents a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms and R represents an alkyl group containing 1 to 4 carbon atoms, where each R may be the same or different.

Particularly effective and desirable compounds of the class of compounds of this invention are:

C17H33CONHCH2CH2CH2N(CH3)2 (N-dimethylaminopropyl oleamide) and C H CONHCH CH N CH 2 (N-dimethylaminoethyl oleamide). Among the other particular compounds of this class of compounds are: C H CONHCH CH N(C H (N dibutylaminoethyl lauramide),

17 31 s) e 12 2 5)z (N-methyl-N-diethylaminohexyl linoleamide) and C l-I CON(C H CH CH N(CH C l-I (N-isopropyl-N-methylisopropylaminoethyl oleamide) The invention also relates to earboxylic acid salts of N-dialkylaminoalkylamides as represented by the formula:

wherein RCO, R, R", and A represent the same groups as described previously. The RCO- in these types of compounds may be the same or different.

The following are particularly effective and desirable examples of this class of anti-blooming agents:

C H CONHCH CH N CH .HOOCR (rosin acid salt of N-dimethylaminoethyl oleamide) and C H CONHCH CH CH N CH .HOOCR (rosin acid salt of N-dimethylaminopropyl oleamide). Among the other particular compounds of this class of compounds are:

C11H23CONHCHzCHgCHzN C H'1)2.HOOCC17H (N-diisopropylarninopropyl lauramide oleate),

C17H31CON( CH CH CH N(CH C H .HOOCC H (N methyl N methylisopropylaminoethyl linoleamide laurate), and

C1'7H33CON 4 9 t s 4 9 2- 17 3s (N-butyl-N-dibutylaminobutyl oleamide oleate) It should be noted that both types of compounds contain a tertiary amine group and an amide group and it is this particular structure which is believed to impart to the compounds their desired characteristics.

In preparing the N-dialkylaminoallrylamides" and their carboxylic acid salts, organic acids are reacted with dialkylaminoalkylamines. Representatives of the class of these amines are:

(CH N CH CH CH NH 3-dimethylaminopropylamine) (CH NCH CH NH (dimethylaminoethylamine),

(CH NCH CH NHCH (dimethylaminoethyl methylamine) (C 21 NCH CH CH CH N HC H (4-dibutylaminobutyl butylamine) and C H CH NCH CH NHCH (methylisopropylaminoethyl methylamine).

Representative of the organic acids that may be used are oleic, linoleic, linolenic, lauric, palmitic, stearic, rosin acids, abietic acid, the mixed acids of tall oil, or mixtures of any of these acids. Triglycerides, such as vegetable and fish oils and animal fats, may be used as ingredients to supply the fatty acids required in carrying out the chemical preparation.

Commercially available acids (which are referred to by letter hereinafter) that are used in the practice of the invention include:

Acid A: (FA No. l)Distilled tall oil containing -93% fatty acids, 3-5% rosin acids.

Acid B: (Acintol D)-Distilled tall oil containing 30- 34% rosin acids, 63-67% fatty acids.

Acid C: (Facoil GN)Refined tall oil containing 54% fatty acids, 37% rosin acids.

Acid D: (Acintol C)Crude tall oil containing 40-44% rosin acids, 47-52% fatty acids.

Acid E: (Acintol R)Tall oil rosin containing 0-3% fatty acids.

Acid F: (Stearic acid)-Rubber grade-45% stearic,

55% palmitic.

Acid G: (TBO)Tallow black oil-88% free fatty acids (26% palmitic, 62% stearic).

In preparing the N-dialkylaminoalkylamides, one mol of organic acid and one mol of dialkylaminoalkylamine are mixed together and heated at -200 C. in a suitable container with suitable agitation. Upon mixing, the amine salt of the organic acid is formed and during the heating process the salt is molecularly dehydrated forming one mol of the N-dialkylaminoalkylamide with the elimination of one mol of Water, as follows:

Reaction on mixing:

RCOOH+NHR-ANR Reaction upon heating:

1 RCO-NR'A-NR" +H O (2)- (1)- RCONR'ANR" +H O The course of the reaction and its completion may be followed by noting the diminishing proportion of carboxylic acid by titration with standard alkali and the diminishing proportion of titratable amine with standard acid. At the completion of the reaction there is substantially no organic acid present and the titratable amine has been reduced to substantially one-half of its original value. The measurement of the eliminated water may also be useful as a guide in determining the completion of the reaction.

In preparing the carboxylic acid salts of the N-dialkylaminoalkylamides, equimolecular proportions of the N-dialkylaminoalkylamide and the organic acid are mixed together at any suitable components are liquids:

positions of the instant invention and the method of using the same:

temperature .atwhich the Example I Using a xylene solution containing 5% pentachlorophenol and 4% of the amide of 3-dimethylaminopropylamine and acid A, maintained at a temperature of 25 0., test pieces of fir (2 inches x 4 inches x inch) are dipped in the solution for thirty seconds, and removed and air dried. Observations for blooming were made from twenty-four hours up to ten days, and it was noted that no blooming occurred.

Example II Using xylene as the solvent, containing 5% pentachlorophenol and 5% of the amide of S-diethylaminopropylamine and acid A, maintained at a temperature of 25 C., test pieces of fir (2 inches x 4 inches x 4 inch) are dipped in the solution for 30 seconds, and removed and dried. Observations for blooming were made from twenty-four hours up to ten days, and it was noted that no blooming occurred.

In separate test runs the same procedure as that just described was carried out except that the acids used in forming the amide were acids B, C, D and F, and it was again noted that no blooming took place during the. observation period.

Example III Example IV A procedure was carried out that is the same as that described in the first paragraph of Example II except that the salt of 1 mol of acid A with the amide was used; and it was noted that no blooming took place during the observation period.

Example V Using a xylol solution containing 5% pentachlorophenol and 5% of the salt of 1 mol of acid E with 1 mol of the amide 3-dimethylaminopropylamine and acid E, maintained at a temperature of 25 C., test pieces of fir are dipped in the solution for 30 seconds, and removed and dried. Observations for blooming were made from twenty-four hours up to ten days, and it Was noted that no blooming occurred.

A procedure that is the same as that describe-d in the foregoing paragraph, except that the salt of 1 mol of acid E with 1 mol of the amide of 3-diethylaminopropylamine and acid E was used, and the results obtained were the same.

Example VI Using a xylene solution containing 5% pentachlorophenol and 4% of an amide of 3-diethylaminopropyl'- amine and acid F, maintained at a temperature of 25 C., test pieces of fir are dipped in the solution for 30 seconds, and removed and dried. Observations for blooming were made from twenty-four hours up to ten days, and it was noted that no blooming occurred.

Substantially the same results are obtained using the procedure of the foregoing paragraph, except that the acid is acid A or acid D.

' Example VII Using a mineral spirits solution containing 5% pentachlorophenol and 5% of the salt of 1 mol of acid D with 1 mol of the amide of 3-dimethylaminopropylamine and acid D, maintained at a temperature of 25 C., test pieces of fir are dipped in the solution for .30 seconds, and removed and dried.

Observations for blooming were made from twenty four hours up to ten days, and it was noted that no blooming occurred.

- a Example VIII Using a mineral spirits solution containing 5% pentachlorophenol and 5% of the salt of 1 mol of acid F with 1 mol of the amide of diethylaminoethylamine and acid F, maintained at a temperature of 25 0., test pieces of fir are dipped in the solution for 30 seconds, and removed and dried. Observations for blooming were made from twenty-four hours up to ten days, and it was noted that no blooming occurred.

The same results are obtained using the procedure of the foregoing paragraph except that the acid used is acid B, C, D or A.

The same results are also obtained using the procedure of the first paragraph of this example except that only a 4% solution of amides of diethylaminoethylamine and acids F or B are used.

Example IX A procedure is carried out that is the. same as that described in the first paragraph of Example I except that mineral spirits is the solvent and a salt of /3 of a mol of acid A with the amide is employed, and the results obtained are the same.

Comparable results are obtained using each of the various other amides or salts thereof hereinbefore described. As mentioned previously, the particular manner in which the pentachlorophenol and the amide compound cooperate is not fully understood, although it is believed to involve some type of chemical association. In any event, blooming is substantially eliminated by the use of the instant amido compounds. Woods, such as pine, for example, the quantities of antiblooming agent used may be slightly smaller than those used with fir, but within thetrange of proportions herein' set'forthjthe, improvement of, the instant invention :is

obtained."

Certain anti-blooming agents have met with commercial acceptance. The anti-blooming agents in current use, however, are associated with one or more of such disadvantages as poor solubility in solvents normally used to prepare the finished treating solution, a tendency to oxidize or undergo other chemical or physical changes so as to produce an insoluble residue in the treating solution either on storage or in use, a tendency to undergo chemical changes to produce or to accelerate the production of undesirable color in the treating solution (which color may stain the wood making it unsatisfactory for many uses), and a tendency to decrease the very desirable water repellency imparted to the wood through treatment or impregnation of the wood with the finished treating solution. The instant anti-blooming agents are unique in that they do not suifer from any of the aforementioned disadvantages.

It will also be appreciated that other additives ordinarily employed in the treatment of Wood with pentachloro- In the case of other- 7 phenol may also be employed without subtracting from the results obtained in the practice of the instant invention.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

I claim as my invention:

1. A composition comprising pentachlorophenol and an amido compound, dissolved in a common solvent, the concentration of the pentachlorophenol being 1 to 30% and the concentration of the amido compound being /2 to 10 times the pentachlorophenol concentration, said amido compound being selected from the group consisting of compounds having the formulae wherein RC0 is an acyl group derived from a carboxylic acid selected from C -C fatty acids and rosin acids, A is a C C alkylene group, R is a radical selected from the group consisting of H and C -C alkyl radicals, and R is a C C alkyl radical.

2. A composition comprising pentachlorophenol and N-dimethylaminopropyleneamide of rosin acid, dissolved in a common solvent, the concentration of the pentachlorophenol being 1% to 30% and the concentration of the N-dimethylaminopropyleneamide of rosin acid being /2 to 10 times the pentachlorophenol concentration.

3. A composition comprising pentachlorophenol and N-dimethylaminopropyleneamide of stearic acid, dissolved in a common solvent, the concentration of the pentachlorophenol being 1% to 30% and the concentration of the N-dimethylaminopropyleneamide of stearic acid being /2 to 10 times the pentachlorophenol concentration.

4. A wood preserving process which comprises contacting the wood with a composition comprising pentachlorophenol and an amido compound, dissolved in a common solvent, the concentration of the pentachlorophenol being 1% to 30% and the concentration of the amido compound being /2 to 10 times the pentachlorophenol concentration, said amido compound being selected from the group consisting of compounds having the formulae wherein RC0 is an acyl group derived from a car'boxylic 5. A Wood preserving process which comprises contacting the wood with a composition comprising pentachlorophenol and N-dimethylaminopropyleneamide of rosin acid, dissolved in a common solvent, the concentration of the penta-chlorophenol being 1% to 30% and the concentration of the N-dimethylaminopropyleneamide of rosin acid being /2 to 10 times the pentachlorophenol concentration; and then drying the wood.

6. A wood preserving process which comprises contacting the wood with a composition comprising pentachlorophenol and N-dimethylaminopropyleneamide of stearic acid, dissolved in a common solvent, the concentration of the pentachlorophenol being 1% to 30% and the concentration of the N-dimethylaminopropyleneamide of stearic acid being /2 to 10 times the pentachlorophenol concentration; and then drying the wood.

7. A composition comprising pentachlorophenol and an amido compound, dissolved in a common solvent, the concentration of the pentachlorophenol 'being 5% and the concentration of the amido compound being substantially equal to the pentachlorophenol concentration, said amido compound being selected from the group consisting of compounds having the formulae wherein RC0 is an acyl group derived from a carboxylic acid selected from C C fatty acids and rosin acids, A is a C -C alkylene group, R is a radical selected from the group consisting of H and C -C4, alkyl radicals, and R is a C -C alkyl radical.

8. A wood preserving process which comprises contacting the wood with a composition comprising pentachlorophenol and an amido compound, dissolved in a common solvent, the concentration of the pentachlorophenol being 5% and the concentration of the amido compound being substantially equal to the pentachlorophenol concentration, said amido compound being selected from the group consisting of compounds having the formulae References Cited in the file of this patent UNITED STATES PATENTS 1,534,525 Hartmann et al Apr. 21, 1925 2,182,080 Hatfield Dec. 5, 1939 2,182,081 Hatfield Dec. 5, 1939 2,757,121 Fahlstrom July 31, 1956 

1. A COMPOSITION COMPRISNG PENTACHLOROPHENOL AND AN AMIDO COMPOUND, DISSOLVED IN A COMMON SOLVENT, THE CENCENTRATION OF THE PENTACHLOROPHENOL BEING 1% TO 30% AND THE CENTRATION OF THE AMIDO COMPOUND BEING 1/2 TO 10 TIMES THE PENTACHLOROPHENOL CONCENTRATION, SAID AMIDO COMPOUND BEING SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS HAVING THE FORMULAE 